This invention relates to sliding clasp fasteners and more particularly to interlocking fastener elements for concealed or masked sliding clasp fasteners.
There are known various forms of concealed sliding clasp fastener elements made of a filamentary member of plastics material which is formed into a coil or meander structure. Such fasteners have found wide use on closure-openings in garments such as for example dresses and skirts. Due to being uniform in thickness and round in cross-section, the filamentary fastener elements of the prior-art have been responsible for a rather bulky appearance of a complete sliding clasp fastener. This is objectionable from the point of view of the merits of a concealed fastener, makes a garment attached with such fastener look awkward, and furthermore hinders the comfort of wear of the garment.
Being round in cross section throughout its length, the known fastener element row would after all fail to be retained in position when subjected to severe external stresses applied as by a reciprocating slider.